The FDA warned consumers and physicians Wednesday that some over-the-counter acne products can cause rare but sometimes life-threatening reactions. The agency said that over the last 40 years it has received 131 reports from users and manufacturers about adverse reactions to products like Proactiv, Neutrogena, MaxClarity, Oxy, Ambi, Aveeno, and Clean & Clear, which contain the ingredients benzoyl peroxide or salicylic acid. About 42% of the bad reactions happened within 24 hours of use, and while no deaths have been reported, 44% of the cases resulted in hospitalizations.